Over the years, efforts have been focused on developing highly active antimicrobial compositions effective against a broad spectrum of microorganisms. However, these compositions also need to have low toxicity against humans and animals and be safe to the environment.
Among the known disinfectants and antimicrobials, hydrogen peroxide is a preferred choice not only due to its potential as a biocide but also due to its low toxicity because it decomposes to give nontoxic oxygen and water. Unfortunately, hydrogen peroxide is not very efficient by itself with its low kill rate against certain organisms although it shows a broad spectrum of biocidal activities and is widely used.
An example of the low kill rate for hydrogen peroxide is that a 6 weight percent (“wt. %”) hydrogen peroxide solution, within a 5 minutes contact time, will only exhibit approximately a 3 Log (i.e., 1000-fold) reduction against Staphylococcus Aureus, and less than a 2 Log (100-fold) reduction against Pseudomonas Aeruginosa. Likewise, a 6000 ppm (i.e., 0.6 wt. %) hydrogen peroxide solution, within a 5 minute contact time, will only exhibit about a 1 log reduction against Staphylococcus Aureus, and less than a 1 Log reduction against Pseudomonas Aeruginosa. 
The killing efficiency of hydrogen peroxide can be improved by using highly concentrated hydrogen peroxide or a longer contact time. However, hydrogen peroxide at a concentration higher than 7.5 wt. % is corrosive. As a result, special handling procedures are required for such concentrations. Additionally, contact times longer than 5 minutes are generally not acceptable for most disinfectant applications.
Because of these difficulties in increasing kill rates, efforts have been made on developing activated hydrogen peroxide formulations to improve the efficacy and killing rate of hydrogen peroxide without having to resort to high hydrogen peroxide concentrations and contact times greater than 5 minutes. The development of these activated hydrogen peroxide formulations is especially important to industries such as the food, health-care, hospitality, and even household use.
One attempt to enhance the efficacy of hydrogen peroxide disinfecting solutions is found in U.S. Pat. No. 5,523,012 to Winterton et al. (“Wintertown”). Wintertown discloses that the addition of anionic sulfosuccinate surfactants to an aqueous, hydrogen peroxide solution improved the killing time against Aspergillus fumigatus to 7.1 minutes. However, the improvement in killing time is still far too long for most disinfectant applications.
Another attempt to enhance the efficacy of hydrogen peroxide disinfecting solutions is found in U.S. Pat. No. 5,264,229 to Mannig et al. (“Mannig”). Mannig discloses a process for reducing the overall bacterial count and increasing the shelf life of the aqueous hydrogen peroxide solution by adding sulfo-based surfactants, such as, alkylaryl sulfonates, sulfates, sulfonates of oils and fatty acid, sulfate of alcohols and sulfosuccinates.
In U.S. Pat. No. 7,658,953, a biocidal hydrogen peroxide composition is enhanced by the addition of a surfactant with a structure: R—O—(CH(Y)—CH2—O)n—CH2—COOH, wherein R is C6 to C12 alkyl, Y is H or CH3, and n is 3-10. The addition of the surfactant was reported to achieve a Log 6 reduction of bacteria in a bacteria suspension within 1 min upon contact with the composition.
Several other patents and patent publications disclose the addition of anionic surfactants based on sulfonic acid to increase the kill rate of an aqueous hydrogen peroxide disinfecting solution: U.S. Pat. No. 7,354,604, U.S. Publication Nos.: 2010/0330196, 2011/0262557, 2011/0129435, 2011/0182958, 2012/0230869, 2012/0177746, 2012/0164237, and European Publication No.: 2338343. The anionic surfactant is chosen from C8 to C16 alkyl aryl sulfonic acids, sulfonated C12 to C22 carboxylic acids, C6 to C22 alkyl diphenyl oxide sulfonic acids, C8 to C22 alkyl sulfonic acids, and C6 to C18 alkyl or alkenyl esters of sulfosuccinic acids.
However, the use of anionic sulfonic acid-based surfactants is less desired in low foaming applications where disinfection, and not cleaning, is the primary function to be achieved.
In view of these strategies for increasing the kill rate of the aqueous hydrogen peroxide disinfecting solutions, there is still a need for more efficacious biocidal compositions that provide shorter contact times (i.e., faster rates of kill, e.g. 5 minutes or less) without an anionic surfactant. There is also a need aqueous hydrogen peroxide disinfecting solutions with a broader spectrum of activity especially against problematic biocidal targets such as Staphylococcus aureus, and Pseudomonas aeruginosa. 